diff --git "a/leetcode3/\354\227\274\355\230\234\354\240\225/66. Plus One.java" "b/leetcode3/\354\227\274\355\230\234\354\240\225/66. Plus One.java"
new file mode 100644
index 00000000..2efd495c
--- /dev/null
+++ "b/leetcode3/\354\227\274\355\230\234\354\240\225/66. Plus One.java"	
@@ -0,0 +1,21 @@
+// O(n)
+
+class Solution {
+    public int[] plusOne(int[] digits) {
+        for (int i = digits.length-1; i>=0; i--) {
+            int digit = digits[i];
+            if (digit == 9) digits[i] = 0;
+            else {
+                digits[i] = digit + 1;
+                break;
+            }
+        }
+        if (digits[0] == 0) {
+            int[] temp = new int[digits.length+1];
+            temp[0] = 1;
+            for (int i = 1; i<temp.length; i++) temp[i] = digits[i-1];
+            return temp;
+        }
+        return digits;
+    }
+}